Forward-biased postural chair

ABSTRACT

A chair having a back portion that is slidably biased with respect to a seat portion. The back portion slides forward against the occupant&#39;s back as the occupant slides forward in the seat. The occupant may set an initial position of the back portion if she or she wishes to sit back in the chair. Optional folding armrests slide together with the back portion. The back portion may also tilt with respect to the seat portion so as to better conform to the occupant&#39;s back.

BACKGROUND

A conventional chair typically contains a seat, a backrest, a base, and armrests. An occupant of the conventional chair sits on top of the seat, which is commonly supported by the base. The occupant typically rests his or her back against the backrest.

The backrest is typically utilized to provide back support to the occupant of a chair. The backrest allows the occupant of the chair to rest his or her back against the backrest, thereby alleviating excess strain.

With some conventional chairs, a user is able to modify the horizontal position of the backrest by adjusting a knob or another similar controller.

With other conventional chairs, the chair has a reclining (i.e., tilting) backrest that is configured to tilt back when an occupant leans against the backrest and to tilt forward to an upright position when an occupant leans forward.

SUMMARY

The above conventional chairs suffer from several deficiencies.

For example, the conventional chair with an adjustment knob allows the user to set the depth of the chair (so long as the depth is at least equal to the depth of the seat of the chair), however, it is not automatically configurable. Thus, when the occupant slides forward in the chair (e.g., out of habit, to reach forward for something, or to use the computer), the backrest will no longer be positioned against the occupant's back, and the occupant will lack back support until he or she moves back in the chair. Therefore, it does not allow for sufficient spinal contact/support in respect to the occupant in a continuous manner. If the occupant remains in the forward position without back support for too long, he or she is placing cumulative postural stress on the cervical, thoracic, and lumbar spine which can manifest over time into spinal pathologies/overuse injuries.

Such lack of proper spinal support also fatigues the muscles that support the spine, therefore leading to the above referenced injuries. Examples of possible injuries caused by this lack of spinal support include cervical strains, headaches, muscle aches, and upper trapezial strains. Furthermore, individuals with degenerative spinal conditions can exacerbate their symptoms, such as joint pain and spinal radiculopathies.

As another example, both of the aforementioned conventional chairs also suffer from the drawback that the backrest is only positionable as far forward as the rear edge of the seat, so that if the user wishes to sit very far forward in the conventional chair, he or she will be unable to have spinal contact/support unless he or she purchases a chair with a smaller seat. Reclining conventional chairs suffer this drawback because the backrest is positioned adjacent the rear of the seat and only tilts up into an upright position.

Reclining conventional chairs also suffer the drawback that as a user slides forward or backward in the conventional chair, the backrest will become tilted at an angle with respect to the user's back/spine and will therefore fail to provide sufficient spinal contact/support.

In contrast to the above-described conventional approaches, embodiments of the present invention provide an improved chair having an automatically adjusting sliding back portion. The user manually sets an initial depth of the chair and as the user slides forward in the chair (whether intentionally or not) a biasing mechanism automatically slides the back portion forward to remain flush against the occupant's back. The back portion may be configurable to slide forward of the rear edge of the seat in order to provide a greater range of positions to allow the occupant to slide very far forward in the chair and still maintain sufficient spinal contact/support.

Further embodiments of the invention include a back portion that is configurable to tilt so that the occupant may adjust the tilt of the back portion to match the desired tilt of the occupant's back. As the seat slides forward, this tilt is maintained.

A further embodiment includes placing armrests on the chair such that the armrests slide together with respect to the excursion of anterior/posterior motion of the back portion. The armrests may also be configured to fold out and away from the seat when the user does not desire to rest his or her arms. The armrests are also capable of adjusting up or down with respect to the occupant's height/elbow level.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features, and advantages of the invention will be apparent from the following description of particular embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.

FIG. 1A is a side view of a chair with a backrest in a forward position.

FIG. 1B is a profile (e.g., offset) view of the chair of FIG. 1A with the backrest in a forward position.

FIG. 2 is a side view of the chair of FIG. 1A with the backrest in the rearmost position.

FIG. 3A is a detailed diagram of a positioner as in FIG. 1A with a locking pin engaged.

FIG. 3B is a detailed diagram illustrating a pull handle component of the controller of FIG. 3A with the locking pin engaged.

FIG. 4A is a detailed diagram of the positioner of FIG. 3A with the locking pin disengaged.

FIG. 4B is a detailed diagram illustrating the pull handle component of the controller of FIG. 3A with the locking pin disengaged.

FIGS. 5A and 5B show the chair of FIG. 1A with the backrest tilted and the armrest swung out. Additional backrest tilting features are also shown. The seat portion is also tilted in this depiction.

FIG. 6 is a flowchart showing a method of operating the chair.

FIG. 7 is a flowchart showing a method of adjusting the backrest of the chair.

DETAILED DESCRIPTION

Embodiments of the invention are directed to chairs having back portions that are forward biased to provide sufficient spinal contact/support to the occupant even as the occupant slides forward in the chair. The occupant may set an initial location for the back portion, and as he or she slides forward in the chair, the back portion will slide forward together with the occupant's back. This prevents the occupant from losing back support as soon as he or she slides forward in the chair, which he or she may do unconsciously out of habit. Therefore, the occupant will not sit for extended periods of time without sufficient spinal contact/support. An embodiment is also directed to a method of operating such a chair.

FIGS. 1A and 1B depict an embodiment of the invention. The figures depict a chair 10, having a seat portion 12, a back portion 14, and a positioner 20. The chair 10 also has an optional base 16 and armrests 18. The positioner 20 includes a controller 26 and a guiding element 28. The back portion 14 connects to the controller 26 by means of a connecting bar 22. The armrests connect to the connecting bar 22 by means of a secondary connector bar 24. The secondary connector bar 24 is hinged so as to rotate around the hinge 90 near the primary connecting bar 22 as described in further detail below.

The controller 26 is configured to slide along the guiding element 28, which is placed along a translational axis 100. The controller 26 also includes a forward-biasing mechanism (such as, for example, a spring), so that it will slide in a forward direction 102 along the translational axis 100 until it reaches the front of the guiding element 28 as long as no force is applied against the back portion 14. The forward-biasing mechanism will be discussed below.

When no one is occupying the chair 10, no force is applied against the back portion 14 in a backward direction 104, so the forward-biasing mechanism with push the controller 26 all the way to the front of the guiding element 28. This causes the back portion 14 to be pushed as far in a forward direction 102 as possible as well, as depicted in FIGS. 1A and 1B. The range of motion of the back portion 14 may vary by design, but in one embodiment, when the back portion 14 is in the most forward position, it will be located halfway between the front and the back of the seat portion 12. However, other embodiments are possible, with the back portion 14 extending even further forward or possibly less far forward, depending on the needs of the intended occupants of the chair 10. For example, the physical characteristics and common sitting habits of the intended occupants may be taken into consideration in making this determination.

When a user wishes to sit in the chair 10, he or she may wish to position the back portion 14 further back so as to be able to sit further back in the chair 10. This procedure will be discussed below, but FIG. 2 depicts the chair 10 with the back portion 14 and the controller 26 pushed all the way in the backward direction 104. The range of motion of the back portion 14 may vary by design, but in one embodiment, when the back portion 14 is in the most rearward position, it will be located directly above the rear edge of the seat portion 12. However, other embodiments are possible, with the back portion 14 extending even further rearward or possibly less far rearward, depending on the needs of the intended occupants of the chair 10. For example, the physical characteristics and common sitting habits of the intended occupants may be taken into consideration in making this determination.

In an alternative embodiment, depicted in FIGS. 1B and 5B, the chair 10 may have two controllers 26 and two guiding elements 28, as well as two sets of connecting bars 22, 24. In this embodiment, there are two redundant positioners 20 for the chair 10. This arrangement is useful because it allows the occupant to control the chair 10 with either hand. It further produces less strain on each controller 26 and guiding element 28.

FIG. 3A depicts one embodiment of the controller 26 and guiding element 28 in more detail. The guiding element includes a hollow pipe 50 having a series of holes or notches 52 positioned thereon along the translational axis 100. The controller 26 has a bushing assembly 64, and a pin assembly 68.

As depicted in detail in FIG. 3B, the pin assembly 68 includes a pull handle 62, a pin 54, having a radius nose 56, a light compression spring 58, which surrounds the pin 54, and a retaining ring 60. Returning to FIG. 3A, the forward-biasing mechanism of the controller 26 is provided by a biasing spring 66 positioned around the pipe 50 behind the bushing assembly 64. The pin 54 is configured to slide into any of the holes 52 on the pipe 50 as the controller 26 overlays over each hole 52.

As depicted in FIGS. 4A and 4B, when the pull handle 62 is pulled in an outward direction 110 away from the pipe 50, the pin 54 is removed from the hole 52 that it was inserted into, and the user is then able to apply pressure in a rearward direction 104 to the back portion 14 (see FIG. 1A) in order to slide the controller 26 along the pipe 50 in the rearward direction 104. When the user ceases to push back and releases the pull handle 62, the light compression spring 58 pushes against the retaining ring 60, which pushes the pin 54 back towards the pipe 50 and the pin 54 engages into a hole 52. As long as the user retains his or her position in the chair 10, the back portion 14 should remain flush against the user's back, thereby providing spinal contact/support.

However, as the user slides forward in the seat portion 12, the force applied by the biasing spring 66 will no longer be counteracted by the force of the user's back, and the back portion 14 will translate forward. As depicted in FIG. 3B, the radius nose ending 56 of the pin 54 is curved such that when a force in a forward direction 102 is applied to the pin 54, the pin 54 will slip out of any hole 52 in which it is positioned. However, a force in the rearward direction 104 will not cause the pin to slip out of the hole 52. Therefore, as the user slides forward in the seat, the force of the biasing spring 66 will push the controller 26 in a forward direction 102 along the pipe, and the pin 54 will slip out of the hole 52 that it is in and reposition in another hole 52 further forward along the pipe 50 until the force of the user's back counteracts the force of the biasing spring 66 again. As the controller 26 slides in the forward direction 102, the connecting bar forces the back portion 14 to also slide in the forward direction 102, allowing the back portion 14 to remain flush against the user's back, thereby providing spinal contact/support.

In one embodiment, the back portion 14 is configurable to tilt to conform to the desired degree of tilt of the user's back. FIG. 5A depicts a tilting control element 80 and a tilting hinge 82. The tilting control element 80 may be activated to allow the back portion 14 to rotate around the tilting hinge 82, as depicted by the arc 106. When the tilting element 80 is deactivated, the tilting hinge 82 locks, and the back portion 14 ceases to rotate around the hinge 82. FIG. 1A depicts the back portion 14 in an upright position. FIG. 5A depicts the back portion 14 in a tilted position.

In one embodiment, the armrests 18 are configurable to swing away from the seat portion 12. FIGS. 1A, 1B, 5A, and 5B depicts hinges 90 on the secondary connector bar 24 as well as armrest control elements 92. When the armrests 18 are positioned in an inward fashion, as depicted in FIG. 1A, the armrests 18 lock into place. When a user activates the armrest control element 92, the armrests 18 unlock, and the user may swing the armrests away from the seat 12 along arc 108 around armrest hinge 90. When this happens, the armrests 18 will lay out away from the seat 14, as depicted in FIGS. 5A and 5B.

FIGS. 5A and 5B also depict the chair 10 with the seat portion 12 tilted backwards relative to the base 16.

FIG. 6 is a flowchart which illustrates a method for controlling the back portion 14 of a chair 10, as described above. In step 1000 the user positions the back portion in an initial position. In step 1100 the user slides forward in the chair 10, allowing the back portion 14 to slide forward against his or her back. In step 1200 the user decides whether or not to reposition the back portion 14. If the user decides to reposition the back portion 14, the user will repeat the method, returning to step 1000. Otherwise, the user will take no further action.

FIG. 7 is a flowchart which further illustrates step 1000 of the method illustrated in FIG. 6. In step 1010 the user deactivates a controller 26 on the chair 10. In step 1020 the user leans back in the chair 10, thereby positioning the back portion 14 towards the rear of the chair 10. In step 1030 the user reactivates the controller 26, thereby locking the controller 26 to prevent further motion in a rearward direction 104.

As noted above, embodiments of the invention are directed to chairs 10 having back portions 14 that are forward biased to provide sufficient spinal contact/support to the occupant even as the occupant slides forward in the chair 10. The occupant may set an initial location for the back portion 14, and as he or she slides forward in the chair 10, the back portion 14 will slide forward together with the occupant's back. This prevents the occupant from losing back support as soon as he or she slides forward in the chair 10, which he or she may do unconsciously out of habit. Therefore, the occupant will not sit for extended periods of time without sufficient spinal contact/support. An embodiment is also directed to a method of operating such a chair.

While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

For example, the positioner 20 was described, by way of example only, as having a pipe 50, a spring 66, and a pin 54, etc. Instead, a hydraulic system could be utilized for the same purpose. Similarly, an electronic system having actuators and sensors and optionally computer control could be used as well.

As another example, the back portion 14 and armrests 18 were described, by way of example only, as connecting to the controller 26 by means of connecting bars 22, 24. Instead, the back portion 14 and armrests 18 could be directly attached to the controller 26, or they could be attached through some other means, such as by an electromagnetic force.

As another example, the armrest control element 92 and tilt control element 80 were depicted as buttons. However, a pull handle could be used for the same purpose. Similarly, the pull handle 62 of the controller 26 was depicted as an actual handle. It could also be implemented as an electronic button, for example.

As another example, the figures depict an office-style chair which swivels and rolls, but any person having ordinary skill in the art will appreciate that the invention may be applied to any kind of chair, for example a 4-legged stationary chair.

As another example, it should be understood that the chair 10 is capable of providing additional features under control of a handle or lever (e.g., see the handle 30 in FIGS. 1A, 1B, 2, 5A, and 5B). For example, in some arrangements, the chair 10 includes a handle 30 which selectively enables and disables operation of the positioner 20. That is, the user is able to direct the chair 10 to operate in automatic or manual bypass mode based on the position of the handle. Along these lines, if the user wishes to vacate the chair 10 without allowing the back portion 14 to slide forward in his or her absence, the user may pull out the handle to deactivate the automatic features of the chair 10 as described above. Subsequently, when the user returns to the chair 10, he or she may push the handle inwards to reactivate the automatic forward biased feature of the chair 10.

As another example, the chair 10 is capable of further including well-known features, such as height control or tilt control of the seat portion 12. Such features are capable of being controlled by a separate control member such as the handle 30. 

1. A seating apparatus to support a user in a sitting position, comprising: a seat portion; a back portion; and a positioner configured to allow the back portion to translate along a translational axis, the positioner being further configured to bias the back portion in a first direction along the translational axis with respect to the seat portion and to inhibit the back portion from moving in a second direction, which is substantially opposite the first direction, with respect to the seat portion.
 2. The seating apparatus of claim 1 wherein the positioner comprises: a guiding element; and a controller; the guiding element configured to guide the controller along the translational axis; the controller being attached to the back portion; the controller having a first tendency to translate in the first direction along the translational axis; the controller having a second tendency to remain stationary when pressure is applied to the back portion in the second direction.
 3. The seating apparatus of claim 2 wherein: when the controller has traveled along the first direction to the end of the guiding element, the back portion is positioned substantially directly over the center of the seat portion; and when the controller has traveled along the second direction to the opposite end of the guiding element, the back portion is positioned substantially adjacent to an edge of the seat portion.
 4. The seating apparatus of claim 2 wherein: when a control element is activated, the back portion is configurable to tilt around a tilt axis which is substantially perpendicular to the translational axis; and when the control element is deactivated the back portion does not tilt about the tilt axis.
 5. The seating apparatus of claim 2 wherein: the seat portion defines a first plane; the back portion defines a second plane; the translational axis is substantially parallel to the first plane and substantially perpendicular to the intersection of the first and second planes.
 6. The seating apparatus of claim 5 wherein: when a control element is activated, the back portion is configurable to tilt around a tilt axis which is substantially parallel to the intersection of the first and second planes; and when the control element is deactivated the back portion does not tilt about the tilt axis.
 7. The seating apparatus of claim 2 wherein the controller is configured to accept an initial position along the guiding element as set by the user.
 8. The seating apparatus of claim 7 wherein: the guiding element is comprised of a tube having a series of collinear holes positioned thereon; a spring is positioned over a portion of the guiding element such that when the spring is compressed it exerts a force on the controller in the first direction; the controller comprises: a pull handle coupled to a pin configured to enter any of the holes on the guiding element; a light compression spring positioned around the pin to exert a force on the pin in the direction of the guiding element; and the end of the pin having a curvature such that when pressure is exerted against the controller in the first direction the pin tends to slide out of a hole on the guiding element, but when no pressure is exerted against the controller in the first direction the pin tends to remain in a hole on the guiding element; and when the pull handle on the controller is pulled away from the guiding element the user may position the controller along the guiding element by applying force against the back portion.
 9. The seating apparatus of claim 2 wherein the controller also attaches to armrests, allowing the armrests to translate together with the back portion.
 10. The seating apparatus of claim 9 wherein the armrests are hinged such that the armrests may be folded out and away from the seating apparatus.
 11. The seating apparatus of claim 1 wherein the positioner comprises: a first guiding element; a first controller; a second guiding element; and a second controller; the first guiding element configured to guide the first controller along the translational axis; the first controller being attached to a first side of the back portion; the second guiding element configured to guide the second controller along the translational axis; the second controller being attached to a second side of the back portion; each controller having a first tendency to translate in the first direction along the translational axis; each controller having a second tendency to remain stationary when pressure is applied to the back portion in the second direction.
 12. A method for controlling the position of a back portion of a chair comprising: setting an initial position of the back portion; and translating the back portion forward when the occupant moves forward in the chair;
 13. The method of claim 12 wherein: the setting step comprises deactivating a controller and leaning back against the back portion until the back portion is in the desired initial position and then reactivating the controller; and the translating step comprises biasing the controller forward as the occupant of the chair moves forward in the chair, such that the forward motion of the controller translates the back portion forward against the occupant's back.
 14. The method of claim 13 wherein: the controller becomes deactivated when a control handle located on the controller is pulled; the controller becomes reactivated when the control handle is released.
 15. A seating apparatus to support a user in a sitting position, comprising: first means for supporting the buttocks of the user; second means for supporting the back of the user; and third means for allowing the first means to translate along a translational axis, the third means being further configured to bias the second means in a first direction along the translational axis with respect to the first means and to inhibit the second means from moving in a second direction, which is substantially opposite the first direction, with respect to the first means. 